New study shows Arctic sea ice extent ~6000 years ago was much less than today

This is interesting, somehow the Earth managed to reduce a good portion of the Arctic Ice Cap during the Holocene Climate Optimum from approximately 10,000-6,000 years ago without the help of the industrial revolution, fossil fuels, or automobile emissions.

This new paper published in Quaternary Science Reviews finds Arctic sea ice extent and thickness was much less than present-day conditions and according to the authors,

“Arctic Ocean sea ice proxies generally suggest a reduction in sea ice during parts of the early and middle Holocene (∼6000–10,000 years Before the Present) compared to present day conditions.”

The authors show how  8 different proxy studies reveal extended periods lasting hundreds of years without perennial sea ice in the Arctic [ice-free conditions], and find solar insolation explains these changes. See figure 4 from the paper below.

The top graph shows simulated annual mean sea ice thickness [orange curve] was much less during the Holocene Climate Optimum ~13,000-6,000 years ago compared to the end of the 20th century at right side of graph. The bottom graph shows multiple proxies of sea ice with darker green indicating periods of less sea ice. Modern sea ice is at high levels in comparison to the rest of the Holocene.

Fig. 4.
Annual mean sea ice thickness for the three different simulations (Panel a) compared with results from published paleo-sea ice studies (Panel b). Black curve: constant surface albedo; red curve: dynamic surface albedo parameterization. The simulation implemented with a dynamic surface albedo parameterization was run from present time and backwards to address the importance of the initial state of the sea ice cover. The annual mean sea ice thickness from this simulation (orange curve) reveals a hysteresis of ∼1000 years. The annual mean insolation at 80°N shown with a stippled curve is based on the algorithm presented by Berger (1978). To compare the results from different paleo-sea ice studies a scale of sea ice concentration was inferred using the approach by Jakobsson et al. (2010). This scale must be considered as highly qualitative because none of the paleo-sea ice proxies provide absolute measures of past sea ice concentrations.

The paper:

Arctic Ocean perennial sea ice breakdown during the Early Holocene Insolation Maximum 

Christian Stranne, Martin Jakobsson, Göran Björk

Abstract

Arctic Ocean sea ice proxies generally suggest a reduction in sea ice during parts of the early and middle Holocene (∼6000–10,000 years Before the Present) compared to present day conditions. This sea ice minimum has been attributed to the northern hemisphere Early Holocene Insolation Maximum (EHIM) associated with Earth’s orbital cycles. Here we investigate the transient effect of insolation variations during the final part of the last glaciation and the Holocene by means of continuous climate simulations with the coupled atmosphere–sea ice–ocean column model CCAM. We show that the increased insolation during EHIM has the potential to push the Arctic Ocean sea ice cover into a regime dominated by seasonal ice, i.e. ice free summers. The strong sea ice thickness response is caused by the positive sea ice albedo feedback. Studies of the GRIP ice cores and high latitude North Atlantic sediment cores show that the Bølling–Allerød period (c. 12,700–14,700 years BP) was a climatically unstable period in the northern high latitudes and we speculate that this instability may be linked to dual stability modes of the Arctic sea ice cover characterized by e.g. transitions between periods with and without perennial sea ice cover.

http://www.sciencedirect.com/science/article/pii/S0277379113004162?np=y

h/t to The Hockey Schtick

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Evan Jones
Editor
March 24, 2014 11:37 am

Yeah, I pointed out that post-1998 “data rewrite” earlier. I see I wasn’t the only one who noticed!

Adrian Metcalfe
March 24, 2014 11:48 am

Alan Robertson says:
“Why don’t you smarten us up? When do you predict the Polar Ice caps will melt? How about those predictions about Arctic ice melt? Were you one of the smarter- than- everyone- else guys telling us that the Arctic would be ice free by 2013? Does Antarctic sea ice increase count?”
So, you deny that the current Arctic melt is due to greenhouse gases. How about publishing your peer reviewed research on what you’ve discovered is causing it?

milodonharlani
March 24, 2014 11:55 am

Adrian Metcalfe says:
March 24, 2014 at 9:24 am
Please state your evidence for earth being closer to the sun 6000 years ago.
Unfortunately for the CACA faithful, Arctic sea ice extent is greater now than for most of the Holocene & perhaps all of the previous interglacial, the Eemian. Arctic sea ice virtually disappeared every summer not just 6000 years ago, but during the whole interval of the Holocene Climatic Optimum (except for the 8200 years ago cooling event) & then again during the peaks of the Egyptian, Minoan, Roman & Medieval Warm Periods. For at least 8500 of the past 10,000 years, arctic sea ice has been less, usually much less, than now.
If modern warming & melting is “unprecedented”, it’s because of the greater than usual rather than less than usual summer sea ice coverage at both poles. Arctic sea ice was similar to now during the first half of the 20th century, too. Antarctic sea ice has probably not been as extensive as now since the depths of the Little Ice Age of c. AD 1700.

milodonharlani
March 24, 2014 12:01 pm

Adrian Metcalfe says:
March 24, 2014 at 11:48 am
There is no evidence whatsoever that GHGs are causing Arctic sea ice to melt. If that were the case, then Antarctic sea ice would also be shrinking instead of growing, but it isn’t. Instead it is setting records for extent during the satellite era, ie since 1979. If increased global air temperature from the GHE were the cause of Arctic ice fluctuations, then both poles should be melting. Land ice is also growing on Antarctica. It stopped shrinking about 3000 years ago.
Ocean currents are the major influence on sea ice extent, not minor air temperature fluctuations. Soot might however be causing surface melt pools on Arctic ice as well.
Arctic sea ice is still well within normal natural limits. It shrank during the 1920s-40s, too, before satellites were around to measure it. And, as above, it went away every summer during the Holocene Climatic Optimum & subsequent warm periods. Its present behavior is nothing new & thus is affected little to not at all by CO2 increases.

Larry Kirk
March 24, 2014 12:10 pm

This correlates well with evidence for 7mya to present (falling) Holocene sea levels evident here on the coast of Western Australia, much of it described here, in this excellent but possibly now hard to obtain Geological Survey of Western Australia publication:
http://www.fishpond.com.au/Books/Geology-and-Landforms-of-Perth-Region-Bob-Gozzard/9781741680720
Probably best sourced direct from GSWA:
http://www2.dmp.wa.gov.au/ebookshop/searchMain.asp
The section describing the detailed carbon dating (from driftwood) and morphology of the post-Holocene optimum coastal advance at the Rockingham-Becher Plain coastal is fascinating, as are the many instances of early Holocene-aged raised beaches, cliff-notches, etc. 2 to 4m above the present sea level (along this ocean coastline of a long-established, tectonically-stable and tectonically-remote continental margin, where such features are far less suspect than say the tectonically-active and recently ice-covered coastlines of northern Europe)

Jimbo
March 24, 2014 12:17 pm

You can add these too.

Abstract
We therefore conclude that for a priod in the Early Holocene, probably for a millenium or more, the Arctic Ocean was free of sea ice at least for shorter periods in the summer. This may serve as an analogue to the predicted “greenhouse situation” expected to appear within our century.
http://adsabs.harvard.edu/abs/2007AGUFMPP11A0203F
Abstract
Arctic sea ice cover was strongly reduced during most of the early Holocene and there appear to have been periods of ice free summers in the central Arctic Ocean. This has important consequences for our understanding of the recent trend of declining sea ice, and calls for further research on causal links between Arctic climate and sea ice.
http://www.sciencedirect.com/science/article/pii/S0277379110003185
Abstract
Calcareous nannofossils from approximately the past 7000 yr of the Holocene and from oxygen isotope stage 5 are present at 39 analyzed sites in the central Arctic Ocean. This indicates partly ice-free conditions during at least some summers. The depth of Holocene sediments in the Nansen basin is about 20 cm, or more where influenced by turbidites.
http://geology.geoscienceworld.org/content/21/3/227.abstract
Abstract
….Nevertheless, episodes of considerably reduced sea ice or even seasonally ice-free conditions occurred during warmer periods linked to orbital variations. The last low-ice event related to orbital forcing (high insolation) was in the early Holocene,…
dx.doi.org/10.1016/j.quascirev.2010.02.010

Jimbo
March 24, 2014 12:26 pm

Gary says:
March 24, 2014 at 5:52 am
It’s 99% modeling results with a tiny bit of support from other studies using paleo data, some of which the authors say is contradictory. The only thing worthwhile coming from it is that models can cut both ways, which hardly supports the paper’s conclusion.

See these studies which don’t rely on modelling.
http://wattsupwiththat.com/2014/03/24/new-study-shows-arctic-sea-ice-extent-6000-years-ago-was-much-less-than-today/#comment-1597538

Jimbo
March 24, 2014 12:30 pm

Leo Geiger says:
March 24, 2014 at 6:17 am
…Climate models are OK now? …

See these
http://wattsupwiththat.com/2014/03/24/new-study-shows-arctic-sea-ice-extent-6000-years-ago-was-much-less-than-today/#comment-1597538

Jimbo
March 24, 2014 12:34 pm

Magma says:
March 24, 2014 at 7:11 am

I am aware of the isolation issue. Now take a look at this close shave.

Abstract
The Early Twentieth-Century Warming in the Arctic—A Possible Mechanism
The huge warming of the Arctic that started in the early 1920s and lasted for almost two decades is one of the most spectacular climate events of the twentieth century. During the peak period 1930–40, the annually averaged temperature anomaly for the area 60°–90°N amounted to some 1.7°C…..
dx.doi.org/10.1175/1520-0442(2004)017%3C4045:TETWIT%3E2.0.CO;2
Abstract
The regime shift of the 1920s and 1930s in the North Atlantic
During the 1920s and 1930s, there was a dramatic warming of the northern North Atlantic Ocean. Warmer-than-normal sea temperatures, reduced sea ice conditions and enhanced Atlantic inflow in northern regions continued through to the 1950s and 1960s, with the timing of the decline to colder temperatures varying with location. Ecosystem changes associated with the warm period included a general northward movement of fish……
dx.doi.org/10.1016/j.pocean.2006.02.011
Abstract
Early 20th century Arctic warming in upper-air data
Between around 1915 and 1945, Arctic surface air temperatures increased by about 1.8°C. Understanding this rapid warming, its possible feedbacks and underlying causes, is vital in order to better asses the current and future climate changes in the Arctic.
http://meetings.copernicus.org/www.cosis.net/abstracts/EGU2007/04015/EGU2007-J-04015.pdf
Monthly Weather Review October 10, 1922.
The Arctic seems to be warming up. Reports from fishermen, seal hunters, and explores who sail the seas about Spitsbergen and the eastern Arctic, all point to a radical change in climatic conditions, and hitherto unheard-of high temperatures in that part of the earth’s surface….
In August, 1922, the Norwegian Department of Commerce sent an expedition to Spitsbergen and Bear Island under Dr. Adolf Hoel, lecturer on geology at the University of Christiania. The oceanographic observations (reported that) Ice conditions were exceptional. In fact, so little ice has never before been noted. The expedition all but established a record, sailing as far north as 81o 29′ in ice-free water. This is the farthest north ever reached with modern oceanographic apparatus…..”
docs.lib.noaa.gov/rescue/mwr/050/mwr-050-11-0589a.pdf
Examiner (Launceston, Tas. – 25 April 1939
…It has been noted that year by year, for the past two decades, the fringe of the Polar icepack has been creeping northward in the Barents Sea. As compared with the year 1900, the total ice surface of this body of water has decreased by twenty per cent. Various expeditions have discovered that warmth-loving species of fish have migrated in great shoals to waters farther north than they had ever been seen before….
http://tinyurl.com/aak64qf
IPCC – AR4
Average arctic temperatures increased at almost twice the global average rate in the past 100 years. Arctic temperatures have high decadal variability, and a warm period was also observed from 1925 to 1945.
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/spmsspm-direct-observations.html

Jimbo
March 24, 2014 12:36 pm

Steven Mosher says:
March 24, 2014 at 8:06 am
who believes models

See these non-model ice free Arctic ocean papers.
http://wattsupwiththat.com/2014/03/24/new-study-shows-arctic-sea-ice-extent-6000-years-ago-was-much-less-than-today/#comment-1597538

Alan Robertson
March 24, 2014 1:26 pm

Adrian Metcalfe says:
March 24, 2014 at 11:48 am
“So, you deny that the current Arctic melt is due to greenhouse gases. How about publishing your peer reviewed research on what you’ve discovered is causing it?”
___________________
Mwahahaaa
I “deny” ever seeing so many logical fallacies packed into a mere two sentences, as you have done.

milodonharlani
March 24, 2014 1:42 pm

J. Philip Peterson says:
March 24, 2014 at 1:29 pm
If that’s for real, then the return of the sun with onset of spring had more dramatic results than usual.

Alan Robertson
March 24, 2014 1:44 pm

J. Philip Peterson says:
March 24, 2014 at 1:29 pm
OK, who’s melting the ice!!!?:
http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_area.png
_____________________
In past, sharp drops (as shown by NORSEX- your link) have usually indicated instrument issues. JAXA shows a lesser drop nd DMI barely registers a drop. There could be another large Arctic cyclone in play, but total area is still w/in 2 stndrd devs. of the 30 yr. avg.

Bruce Cobb
March 24, 2014 1:44 pm

J. Philip Peterson says:
March 24, 2014 at 1:29 pm
OK, who’s melting the ice!!!?:
http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_area.png
Good question! Anyone seen Al Gore lately?

phlogiston
March 24, 2014 3:45 pm

Magma, jai mitchell
The Arctic ice is not gone yet. Plus it was just as low a hundred years ago.

Randy
March 24, 2014 3:48 pm

joe says:
March 24, 2014 at 8:39 am
Actually a study recently proved this is NOT likely to happen from the frozen tundra recently. They actually warmed up the land over years, as might simulate climatic change. The methane was simply not released from the soil as ASSUMED. So this part of the methane bubble claim is NOT supported by the closest thing to real world data we have. It is very telling how the field still relies on old assumptions in light of this.
https://www.sciencenews.org/article/warming-may-not-release-arctic-carbon
It is VERY telling if you pop keywords related to this into a search engine. you will find hordes of claims about how big of a timebomb the tundra soils stored carbon is. You will have to really look if you want to see the only study that actually TESTED the claims, and literally heated up the soil over decades, and found the long time claims false. Meanwhile all these sources claiming to be pushing the latest science, or climate facts and variation sof such memes somehow missed the most comprehensive data we have on the subject….

phlogiston
March 24, 2014 3:52 pm

So an Arctic ice free in summer is an attractor. But if getting it that way via a warm gulf stream requires too much heat piracy from the SH with the Caribbean current, the ensuing and reciprocal Antarctic cooling could destabilise the system leading to a bipolar seesaw of growing magnitude, a signature of both the start and end of an interglacial (e.g. Tzedakis).

milodonharlani
March 24, 2014 3:56 pm

jai mitchell says:
March 24, 2014 at 8:46 am
During the Holocene Climatic Optimum, Arctic sea ice extent was much lower than now, not the same.
During HCO summers, Arctic sea ice virtually disappeared. Yet the polar bears survived. Indeed thrived.

March 24, 2014 4:31 pm

Alan Robertson says:
March 24, 2014 at 7:18 am
Magma says:
March 24, 2014 at 7:11 am
—————————————-
Alan…I think you were correct with your remark regarding Magma. For some reason he assumes that everyone reading this has overlooked or forgotten about the insolation changes. Then as you point out, he has nothing to add to further anyone,s understanding of why the Arctic is being impacted in recent decades.

Richard M
March 24, 2014 4:42 pm

J. Philip Peterson says:
March 24, 2014 at 1:29 pm
OK, who’s melting the ice!!!?:

It’s not melting if you took the time to look at any of the satellite pictures (one of them shows an a missing area). Clearly, this is an instrument (or software) problem. It will disappear shortly.

March 24, 2014 4:43 pm

jauntycyclist says:
“ulric -nice contextualising pic.
i think if people still looking for eloquent images [a previous thread] showing global temps and where we are then yours sums it up.”
No it does not, Greenland temp’ moves in opposition to the Temperate Zone through the Holocene.
http://snag.gy/BztF1.jpg

March 24, 2014 5:40 pm

Alan Robertson says:
March 24, 2014 at 1:44 pm
J. Philip Peterson says:
March 24, 2014 at 1:29 pm
OK, who’s melting the ice!!!?:
————————————————
Looking at NSIDC, JAXA, and the DMI it can be seen that in the last 2 days there has been a small downward shift in the trend. This small downturn comes after a sharp upward trend that lasted for 2 weeks. The sea ice had dipped below -2sd for 2 days before it then turned and almost made it to the 2000s trend line. This is similar top what the sea ice did in 2011/12. In the 3rd week of February 2012 at mid moon, the Arctic sea ice started a sharp upward movement. Right at the mid moon on the 8th of this month, the Arctic sea ice took a sharp upward turn. NSIDC shows the current spot sits in the middle of the -2sd trend.
Antarctic sea ice is on the upswing again and is close to the +2sd line. the trend will likely cross above the +2sd line within 2 weeks.

climateace
March 24, 2014 7:18 pm

‘ wws says:
March 24, 2014 at 7:20 am
“other real scientists in my home country of Somerset discovered that the lake-village dwellers ate Pelicans for breakfast (European birds now found only in Greece and the Danube delta)!”
I take it that there is a difference between a real scientist and a Skeptic Memer who abuses a fact or two about pelicans in order to make a spurious, non-scientific point about climate.
Just for the record, Louisiana and the rest of the Gulf Coast are lousy with those things.’
They are different species from the species wws is referring too, but the two north american pelican species are indeed doing well.
It would be difficult to argue that pelicans have become extinct in Britain because of climate. The Dalmatian Pelican (fossils of which have been found in GB) still occurs as a vagrant in northern europe. Various species of pelicans occur naturally in climates similar to those of Britain. Various species of pelicans are found in captivity in London Parks where they sometimes do nasty things to pigeons – like catching them and swallowing them alive:

As with other local, national and regional (as opposed to global) extinctions of various pelican species, the most likely recent extinction drivers are human activities: in the case of GB, 64 million people crowded into in a country that can no longer feed itself but has to import around three month’s worth of food annually. My guess is that the most likely factor is that pelicans have a tendency to abandon eggs or nestlings if disturbed.
Most of the world’s eight pelican species have a sound conservation status.